It is known to reconnect transected nerves, blood vessels, tendons and the like using microsurgical techniques. However, using present methods, results are unpredictable and depend on a number of factors including the skill of the surgeon, the type of injury sustained and the time elapsed between the injury and the repair. In addition, while the techniques for rejoining the proximal and distal stumps of the various cable-like organs are substantially analogous to one another, the results vary widely depending on the particular structure being reconnected. This is especially true with respect to nerve fibers where at the zone of a cut, all pathways are destroyed and the ability of the nerve to transmit signals is completely lost. The nerve will sometimes reconnect itself due to the action of neurites that are born in the proximal stump that grow at random in the area of the cut. After suture, most sprouts will reach the distal stump and, therefore, penetrate structures that have not been damaged. From there on, they will follow steadily and blindly the guide that they have found, without branching or changing direction. At the suture line, however, considerable interlacing of the regenerating fibers occurs, so that many neurites fail to enter the appropriate endoneurial tube in the distal stump which results in less than optimal restoration of the motor function.
To decrease the interlacing of regenerating neurites in a transected and repaired nerve, it is necessary to keep the fibers in good longitudinal alignment with their stumps to prevent or at least to minimize whorling of the nerve structures. However, in practice keeping the fibers in longitudinal alignment is quite difficult. Nerve fibers are so soft that the slightest stress disrupts them and modifies their direction. In addition to the whorling problem mentioned above, at the tip of the transected nerve, the additional problems of buckle and wave must be addressed during reconnection. Suturing the stumps considerably worsens the situation because no matter how fine the stitches are, they impart irregular stresses on the nerve. There is a combination of traction at the suture points and of slackness between them. This irregular stress on the nerve sheaths results in a profound longitudinal disorganization of the fibers inside the faciles.
A partial solution to the problem is suggested by U.S. Pat. No. 4,586,504 to de Medinaceli entitled "Nerve Connector and Method." The patent teaches a method and apparatus for obtaining enhanced results when rejoining the proximal and distal stumps of transected cable-like organs, such as nerves, by removing all foreign matter from the zone of reunion thereby equalizing the stresses in the zone. This is accomplished by suturing the nerve stumps in contacting relation on to a template such that the sutures are 1.5-2 diameters away from the zone of reunion according to a postulate derived from the principle of Saint-Venant and discussed in my paper entitled "How to Correctly Match 175,000 Neurites The Postulates For A Quick Solution", BioSystems, Vol 20, pp 307-315, 1987.
More specifically, the de Medinaceli patent teaches a nerve connecting device on which there are transcribed the lines and pattern necessary to make a reunion of the nerve stumps. The lines and pattern indicate the nerve diameter, the general position of the nerve on the device, the distance at which the fixation stitches must be placed from the tip of each stump and the amount of tissue that must be trimmed from the stumps.
To use the prior art de Medinaceli apparatus it was first necessary to assess the diameter of the nerve. This diameter measurement was then confirmed by placing the nerve connector corresponding to the measured diameter beneath the nerve and visually making a determination as to whether the nerve diameter corresponded roughly to the distance between a pair of parallel lines inscribed on the connector. In operation, the sutures were loosely applied to one of the stumps and to the connector. Then the connector was pulled towards the other stump and it was similarly sutured to the connector. Thereafter, the first stump sutures were tightened, stretching the stump and bringing it into overlying relation on top of the connector so that the two stumps laid side-by-side overlapping one another. In the next step, the stumps were trimmed and placed end to end prior to folding over flaps on the template and suturing it closed.
The foregoing system, while effective, was not without its drawbacks as the process of rejoining a transected nerve was haphazard due to the fact that the initial approximation of nerve diameter had to be made without any measurement apparatus. In addition, guide lines had to be present on the template in one form or another, thus introducing undesirable foreign inks into the body of a patient, or alternatively, complicating the production process by embossing or scribing them onto the connector. Also, when the nerve stumps were trimmed, the blades often cut into the connector, thus weakening it and decreasing its efficacy. Furthermore, in the prior system, there was a possibility that the surgeon might trim or cut the "flaps" of the connector thereby creating a danger of stricture to the nerve.
It is accordingly an object of the invention to provide a nerve connector which does not introduce any foreign inks into the body.
Another object of the invention is to minimize the potential for error by eliminating guide lines from the connector.
A further object is to simplify the process of manufacturing the connector by eliminating therefrom both printed and embossed lines.
A still further object of the invention is to eliminate the possibility of accidentally cutting the connector.
A still further object of the invention is to eliminate the need to wrap the nerve in the connector.
Yet another object of the invention is to reduce the size of the connector, thereby minimizing the disturbance to the neighboring body tissues.